What digit $A$ will make the number $83A5$ divisible by $9$?
Explanation: A number is divisible by $9$ if and only if the sum of its digits is also divisible by $9$.  So $9$ divides $8 + 3 + A + 5 = 16 + A$.  Here, the only digit that works is $A = \boxed{2}$, which yields $16 + A = 18$.